Characterization and Optimization of AlSi10Mg-Components Produced by Selective Laser Melting

Abstract

The additive manufacturing process known as selective laser melting (SLM) produces metallic parts directly from a computer aided design (CAD)-model, by selectively melting metallic powder particles together in a layer-by-layer manner. Due to the high thermal conductivity and high reflectivity of aluminium, challenges related to pore defects arise when producing aluminium components in the SLM-process. This thesis aims to investigate and optimize the process parameters to minimize porosity, based on results gathered from earlier work conducted at NTNU by Tobias Rønneberg and Alisher Djuraev. The powder used in the production is also investigated. The material investigated in this thesis is an AlSi10Mg-casting alloy. The goal of the SLM-production was to build components with minimal porosity fraction. The specimens were investigated through optical microscopy and were mechanically tested. The results show that AlSi10Mg-components with relative density above 99,6 % can be produced by applying the proper combination of process parameters in the SLM-machine. The remaining pores in the components were found to be small, spherical metallurgical pores. The unique material structure was characterized through microscopy. Processing temperature proved to play a significant role in both mechanical properties and the densification mechanisms.